Sandback is primarily known for his Minimalist works made from lengths of colored yarn. The artist's early interest in stringed musical instruments led him to make dulcimers and banjos as a teenager.[2] In 1967, he produced the sculpture that would establish the terms of his mature work. Using string and wire, he outlined the shape of a 20-foot-long 2-by-4 board lying on the floor.[3] Though he employed metal wire and elastic cord early in his career, the artist soon dispensed with mass and weight by using acrylic yarn.[4] His yarn, elastic cord, and wire sculptures define edges of virtual shapes that ask the viewer's brain to perceive the rest of the form. In that way his work can be considered visionary or imaginative, as well as minimal and literal. Indeed, Sandback was fond of installing "corner" pieces whose shadows assist with this form completion process. In describing his work he stated, "It's a consequence of wanting the volume of sculpture without the opaque mass that I have the lines." and "I did have a strong gut feeling from the beginning though, and that was wanting to be able to make sculpture that didn't have an inside." [5] Sandback himself referred to his sculptures operating in pedestrian space, acknowledging both the viewer’s movement through a space and as something to be engaged actively.[6]

Sandback was one of a small group of avant garde artists sponsored by the Dia Art Foundation. In 1981 the Dia Art Foundation initiated and maintained a museum of his work, The Fred Sandback Museum in Winchendon, Massachusetts, which was closed in 1996. Dia presented exhibitions of his works in 1988 and in 1996–97. In 2007 the Fred Sandback Archive, a non-profit organization was established primarily to create and maintain an archival resource on Sandback's work. At Christie's New York, his four-part installation Untitled (1968) was sold for $266,500 in November 2010.[7]

A detailed exhibition history and bibliography, 1967–2005, together with the artist’s collected writings and interviews, is published in the exhibition catalogue Fred Sandback, Vaduz: Kunstmuseum Liechtenstein, 2005; an updated history from 2004–2009 is published in the exhibition catalogue Fred Sandback, New York: David Zwirner; Göttingen:Steidl, 2009. The years 2009–2012 are covered in the exhibition catalogue Fred Sandback: Decades, New York: David Zwirner; Santa Fe: Radius Books, 2013; 2013–2016 is covered in Fred Sandback: Vertical Constructions. New York: David Zwirner Books, 2017.

A complete exhibition history and bibliography is available online at fredsandbackarchive.org.